Methods to facilitate cooling syngas in a gasifier

ABSTRACT

A method of cooling syngas in a gasifier is provided. The method includes channeling cooling fluid through at least one tube-bundle that includes at least three tubes coupled together within a radiant syngas cooler and extends through a reaction zone of the gasifier, and circulating reactant fluid around the at least one tube-bundle to facilitate transferring heat from the reactant fluid to the cooling fluid.

BACKGROUND OF THE INVENTION

This invention relates generally to integrated gasificationcombined-cycle (IGCC) power generation systems, and more specifically toa gasifier that includes an integral radiant syngas cooler.

At least some known IGCC systems include a gasification system that isintegrated with at least one power-producing turbine system. Forexample, known gasifiers convert a mixture of fuel, air or oxygen,steam, and/or limestone into an output of partially combusted gas,sometimes referred to as “syngas”. The hot combustion gases are suppliedto the combustor of a gas turbine engine, which powers a generator thatsupplies electrical power to a power grid. Exhaust from at least someknown gas turbine engines is supplied to a heat recovery steam generatorthat generates steam for driving a steam turbine. Power generated by thesteam turbine also drives an electrical generator that provideselectrical power to the power grid.

At least some know gasification systems use a separate gasifier, and aphysically-large radiant cooler to gasify bottoms, recover heat, and toremove solids from the syngas, to make the syngas useable by othersystems. Such additional components and ancillary equipment needed tosupport operation of the gasifier and the radiant cooler add to thecomplexity, the capital expense, and operational manpower of the system.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a method of cooling syngas in a gasifier is provided.The method includes channeling cooling fluid through at least onetube-bundle that includes at least three tubes coupled together within aradiant syngas cooler and extends through a reaction zone of thegasifier, and circulating reactant fluid around the at least onetube-bundle to facilitate transferring heat from the reactant fluid tothe cooling fluid.

In a further embodiment, a radiant cooler for use in a gasifier isprovided. The cooler includes at least one cooling tube-bundlecomprising at least three cooling tubes, and at least two connectionmembers. A first of the connection members is coupled between a firstand a second of the at least three cooling tubes. A second of theconnection members is coupled between a third of the at least threecooling tubes and the first connection member. A portion of the firstconnection member mates substantially flush against a portion of thesecond connection member.

In a further embodiment, a gasifier is provided. The gasifier includes areaction zone, and a radiant cooler extending through the reaction zone.The radiant cooler includes at least one cooling tube-bundle comprisingat least three cooling tubes, and at least two connection members. Afirst of the connection members is coupled between a first and a secondof the at least three cooling tubes. A second of the connection membersis coupled between a third of the at least three cooling tubes and thefirst connection member. A portion of the first connection member matessubstantially flush against a portion of the second connection member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary known integratedgasification combined-cycle (IGCC) power generation system.

FIG. 2 is a schematic view of an exemplary gasifier that includes anintegral radiant syngas cooler and that may be used with the systemshown in FIG. 1.

FIG. 3 is a cross-sectional view of an exemplary gasifier shown in FIG.2.

FIG. 4 is an enlarged plan view of a portion of an integral radiantsyngas cooler that may be used with an exemplary gasifier shown in FIG.2.

FIG. 5 is an enlarged plan view a portion of an alternative embodimentof an integral radiant syngas cooler that may be used with an exemplarygasifier shown in FIG. 2.

FIG. 6 is an enlarged plan view of a portion of another alternativeembodiment of an integral radiant syngas cooler that may be used with anexemplary gasifier shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic diagram of an exemplary known integratedgasification combined-cycle (IGCC) power generation system 50. IGCCsystem 50 generally includes a main air compressor 52, an air separationunit 54 coupled in flow communication to compressor 52, a gasifier 56coupled in flow communication to air separation unit 54, a gas turbineengine 10, coupled in flow communication to gasifier 56, and a steamturbine 58.

In operation, compressor 52 compresses ambient air that is channeled toair separation unit 54. In some embodiments, in addition to compressor52 or alternatively, compressed air from gas turbine engine compressor12 is supplied to air separation unit 54. Air separation unit 54 usesthe compressed air to generate oxygen for use by gasifier 56. Morespecifically, air separation unit 54 separates the compressed air intoseparate flows of oxygen (O₂) and a gas by-product, sometimes referredto as a “process gas”. The process gas generated by air separation unit54 includes nitrogen and will be referred to herein as “nitrogen processgas” (NPG). The NPG may also include other gases such as, but notlimited to, oxygen and/or argon. For example, in some embodiments, theNPG includes between about 95% and about 100% nitrogen. The O₂ flow ischanneled to gasifier 56 for use in generating partially combustedgases, referred to herein as “syngas” for use by gas turbine engine 10as fuel, as described below in more detail. In some known IGCC systems50, at least some of the NPG flow is vented to the atmosphere from airseparation unit 54. Moreover, in some known IGCC systems 50, some of theNPG flow is injected into a combustion zone (not shown) within gasturbine engine combustor 14 to facilitate controlling emissions ofengine 10, and more specifically to facilitate reducing the combustiontemperature and reducing nitrous oxide emissions from engine 10. In theexemplary embodiment, IGCC system 50 includes a compressor 60 forcompressing the nitrogen process gas flow before being injected into thecombustion zone.

Gasifier 56 converts a mixture of fuel, O₂ supplied by air separationunit 54, steam, and/or limestone into an output of syngas for use by gasturbine engine 10 as fuel. Although gasifier 56 may use any fuel, insome known IGCC systems 50, gasifier 56 uses coal, petroleum coke,residual oil, oil emulsions, tar sands, and/or other similar fuels. Insome known IGCC systems 50, the syngas generated by gasifier 56 includescarbon dioxide. In the exemplary embodiment, syngas generated bygasifier 56 is cleaned in a clean-up device 62 before being channeled togas turbine engine combustor 14 for combustion thereof. Carbon dioxide(CO₂) may be separated from the syngas during clean-up and, in someknown IGCC systems 50, may be vented to the atmosphere. Gas turbineengine 10 drives a generator 64 that supplies electrical power to apower grid (not shown). Exhaust gases from gas turbine engine 10 arechanneled to a heat recovery steam generator 66 that generates steam fordriving steam turbine 58. Power generated by steam turbine 58 drives anelectrical generator 68 that provides electrical power to the powergrid. In some known IGCC systems 50, steam from heat recovery steamgenerator 66 is supplied to gasifier 56 for generating syngas.

Furthermore, in the exemplary embodiment, system 50 includes a pump 70that supplies steam 74 from steam generator 66 to a radiant syngascooler (not shown) within gasifier 56 to facilitate cooling the syngasflowing within gasifier 56. Steam 74 is channeled through the radiantsyngas cooler wherein water 72 is converted to steam 74. Steam 74 isthen returned to steam generator 66 for use within gasifier 56 or steamturbine 58.

FIG. 2 is a schematic view of an exemplary advanced solids removalgasifier 200 that includes an integral radiant syngas cooler 300.Gasifier 200 may be used with an IGCC, such as system 50 (shown in FIG.1). In the exemplary embodiment, gasifier 200 includes an upper shell202, a lower shell 204, and a substantially cylindrical vessel body 206extending therebetween. A feed injector 208 penetrates upper shell 202to enable a flow of fuel to be channeled into gasifier 200. Morespecifically, the fuel flowing through injector 208 is routed throughone or more passages defined in feed injector 208 and is dischargedthrough a nozzle 210 in a predetermined pattern 212 into a combustionzone 214 defined in gasifier 200. The fuel may be mixed with othersubstances prior to entering nozzle 210, and/or may be mixed with othersubstances when discharged from nozzle 210. For example, the fuel may bemixed with fines recovered from a process of system 50 prior to enteringnozzle 210 and/or the fuel may be mixed with an oxidant, such as air oroxygen, at nozzle 210 or downstream from nozzle 210.

In the exemplary embodiment, combustion zone 214 is defined as avertically-oriented, generally cylindrical space, that is substantiallyco-aligned with nozzle 210 in a serial flow communication. An outerperiphery of combustion zone 214 is defined by a refractory wall 216that includes a structural substrate, such as an Incoloy pipe 218 and arefractory coating 220 that substantially resists the effects of hightemperatures and high pressures contained within combustion zone 214. Inthe exemplary embodiment, an outlet end 222 of refractory wall 216includes a convergent outlet nozzle 224 that facilitates maintaining apredetermined backpressure in combustion zone 214, while permittingproducts of combustion and syngas generated in combustion zone 214 toexit combustion zone 214. The products of combustion may include gaseousbyproducts, slag formed generally on refractory coating 220, and/or fineparticular matter carried in suspension with the gaseous byproducts.

After exiting combustion zone 214, flowable slag and solid slag aregravity-fed into a lockhopper 226 coupled to lower shell 204. Lockhopper226 is maintained with a level of water that quenches the flowable slaginto a brittle solid material that may be broken into smaller pieceswhen removed from gasifier 200. In the exemplary embodiment, lockhopper226 captures approximately ninety percent of fine particulate exitingcombustion zone 214.

In the exemplary embodiment, a first annular passage 228 at leastpartially surrounds combustion zone 214. Passage 228 is partiallydefined by refractory wall 216 at an inner periphery, and by acylindrical shell 230 that is substantially coaxially aligned withcombustion zone 214 at a radially outer periphery of passage 228.Passage 228 is sealed at the top by an upper flange 232. The gaseousbyproducts and any remaining fine particulate are channeled from adownward direction 234 in combustion zone 214 to an upward direction 236in passage 228. The rapid redirection at outlet nozzle 224 facilitatesseparating fine particulate and slag separation from gaseous byproducts.

The gaseous byproducts and any remaining fine particulate are channeledupward through passage 228 to an outlet 238. As the gaseous byproductsare channeled through passage 228, heat may be recovered from thegaseous byproducts and the fine particulate. For example, in oneembodiment, the gaseous byproducts enter passage 228 at a temperature ofapproximately 2500° Fahrenheit and exit passage 228 at a temperature ofapproximately 1800° Fahrenheit. The gaseous byproducts and fineparticulates are discharged from passage 228 through outlet 238 and arechanneled into a second annular passage 240 wherein the gaseousbyproducts and fine particulates are redirected to a downward flowdirection 241. As gaseous byproducts and fine particulates flow throughpassage 240, heat may be recovered using for example, superheat tubes242 that transfer heat from the flow of gaseous byproducts and the fineparticulates to steam flowing through superheat tubes 242. For example,in one embodiment, the gaseous byproducts enter passage 240 at atemperature of approximately 1800° Fahrenheit and exit passage 240 at atemperature of approximately 1500° Fahrenheit.

When the flow of gaseous byproducts and the fine particulates reach abottom end 244 of passage 240, passage 240 converges toward lockhopper226. More specifically, at bottom end 244, the flow of gaseousbyproducts and the fine particulates is channeled upward through a waterspray 246 that desuperheats the flow of gaseous byproducts and the fineparticulates. Heat removed from the flow of gaseous byproducts and thefine particulates tends to vaporize water spray 246 and agglomerate thefine particulates such that the fine particulates form a relativelylarger ash clod that falls into lower shell 204. The flow of gaseousbyproducts and the remaining fine particulates are channeled in areverse direction towards a perforated plate 248 that circumscribesbottom end 244. A level of water is maintained above perforated plate248 to facilitate removing additional fine particulate from the flow ofgaseous byproducts. As the flow of gaseous byproducts and the remainingfine particulates percolate through perforated plate 248, fineparticulates contained in the flow are entrapped in the water andcarried through the perforations into a sump formed in lower shell 204.A gap 250 defined between lockhopper 226 and lower shell 204 enables thefine particulates to flow into lockhopper 226 wherein the fineparticulates are facilitated to be removed from gasifier 200.

An entrainment separator 254 encircles an upper end of lower shell 204.More specifically, separator 254 is above perforated plate 248 and abovethe level of water covering perforated plate 248. Entrainment separator254 may be for example, a cyclonic or centrifugal separator thatincludes a tangential inlet or turning vanes that impart a swirlingmotion to the gaseous byproducts and the remaining fine particulatesflowing therethrough. The particulates are thrown outward by centrifugalforce to the walls of separator 254 wherein the fine particulatescoalesce and are gravity-fed to the separator lower shell 204.Additionally, any remaining fine particulates impact a mesh pad,agglomerate with other particulates and are flushed to lower shell 204.

Alternatively, entrainment separator 254 can be of a blade type, such asa chevron separator or an impingement separator. In a chevron separator,the gaseous byproducts pass between blades and are forced to travel in atortuous or zigzag pattern. The entrained particulates and any liquiddroplets cannot follow the gas streamlines, and impinge against theblade surfaces prior to coalescing, wherein the particulates aregravity-fed into lower shell 204. Features such as hooks and pockets,can be added to the sides of the blades to facilitate improvingparticulate and liquid droplet capture. In addition, chevron grids canbe stacked to provide a series of separation stages. Similarly,impingement separators create a cyclonic motion as gaseous byproductsand fine particulates pass over curved blades. A spinning motion isimparted that causes the entrained particulates and any liquid dropletsto be forced against to the vessel walls, wherein the entrainedparticulates and any liquid droplets may be collected in lower shell204.

The flow of gaseous byproducts and any remaining fine particulates enterseparator 254 wherein substantially all of any remaining entrainedparticulate and/or liquid droplets are removed form the flow of gaseousbyproducts. The flow of gaseous byproducts exits gasifier 200 through anoutlet 256 for further processing.

In the exemplary embodiment, gasifier 200 also includes a radiant syngascooler 300 that is coupled within passage 228. Moreover, in oneembodiment, cooler 300 includes a plurality of platens 320 spacedcircumferentially about a centerline CL of cylindrical vessel 206. Eachplaten 320 extends radially outward from refractory wall 216 towardsvessel body 206, and is positioned within passage 228 to facilitatecooling syngas flowing through passage 228. Moreover, each platen 320includes an inlet 302, an outlet 304, and a plurality of cooling tubes306 extending therebetween. In the exemplary embodiment, each platen 320includes approximately 12 cooling tubes 306. In an alternativeembodiment, each platen 320 includes any suitable number of coolingtubes 306 that facilitate cooling the syngas in passage 228. In theexemplary embodiment, cooling tubes 306 form a plurality oftube-bundles. A tube-bundle includes a plurality of cooling tubes 306coupled to one another with connection members such that the coolingtubes are positioned in various configurations, as will be described inmore detail below.

In the exemplary embodiment, inlet 302 extends from a first end 308 ofcooling tube 306 to an exterior 310 of cylindrical vessel 206.Similarly, outlet 304 extends from a second end 312 of cooling tube 306to exterior 310. In the exemplary embodiment, inlet 302 is positionedbelow outlet 304. In an alternative embodiment, inlet 302 is positionedabove outlet 304 or substantially planar therewith.

During operation, pump 70 channels steam 74 from steam generator 66through inlet 302 and into cooling tube first end 308. Alternatively,steam 74 may be channeled to inlet 302 from any suitable source. Steam74 is then channeled through cooling tube 306 towards second end 312.Simultaneously, syngas channeled through passage 228 flows aroundcooling tube 306 to facilitate a heat exchange between the syngas andsteam 74. Specifically, because steam 74 has a temperature that is lessthan the temperature of the syngas, steam 74 absorbs heat from thesyngas to facilitate cooling the syngas.

Furthermore, in addition to cooling the syngas, cooling tube 306facilitates cooling of refractory wall 216. More specifically, as steam74 absorbs heat from the syngas, a higher temperature steam 74 isproduced in cooling tube 306 and is discharged through outlet 304. Inthe exemplary embodiment, steam 74 is discharged from outlet 304 tosteam generator 66 for further use within system 50. In an alternativeembodiment, steam 74 is channeled to any suitable portion of system 50and/or any other system that requires steam. In another alternativeembodiment, steam 74 is discharged from system 50 to the atmosphere.

FIG. 3 is a cross-sectional view of gasifier 200 taken along line 3-3(shown in FIG. 2). FIG. 4 is an enlarged plan view of a portion ofintegral radiant syngas cooler 300.

In the exemplary embodiment, cooler 300 includes a plurality of platens320. Each platen 320 is positioned within passage 228 and extendssubstantially radially outward from refractory wall 216 towards vesselbody 206. Cooling tubes 306 are coupled together by a plurality ofconnection members 322 (shown in FIG. 2) to facilitate cooling syngasflowing through passage 228. In the exemplary embodiment, cooler 300includes thirteen platens 320. In an alternative embodiment, cooler 300includes any number of platens 320 that enables gasifier 200 to functionas described herein.

In the exemplary embodiment, platens 320 are positionedcircumferentially around combustion zone 214. More specifically, in theexemplary embodiment, platens 320 are spaced substantially equally aboutgasifier 200. Accordingly, in the exemplary embodiment, each platen 320is spaced approximately 27.69 degrees apart from eachcircumferentially-adjacent platen 320. In an alternative embodiment,cooler 300 includes fifteen platens 320, and platens 320 are spacedapproximately 24 degrees apart from each other. In another alternativeembodiment, platens 320 are not circumferentially equi-spaced aboutcombustion zone 214.

In the exemplary embodiment, each platen 320 includes at least threecooling tubes 306. In an alternative embodiment, each platen 320includes any number of cooling tubes 306 that enable the syngas inpassage 228 to be cooled, as described herein. Specifically, in theexemplary embodiment, a first platen cooling tube 330 is located adistance 331 radially outward from refractory wall 216 and is coupled torefractory wall 216 with at least one connection member 322. A secondplaten cooling tube 332 is located a distance 333 radially outward fromcooling tube 330. In the exemplary embodiment, distance 333 isapproximately the same as distance 331. At least one connection member322 secures cooling tube 332 to cooling tube 330. A third platen coolingtube 334 is located a distance 335 radially outward from cooling tube332. In the exemplary embodiment, distance 335 is approximately the sameas distance 331, such that cooling tubes 330 and 334 are substantiallyequi-spaced from cooling tube 332. Alternatively, distance 335 isdifferent than distance 331. At least one connection member 322 couplescooling tube 334 to cooling tube 332. Moreover, in the exemplaryembodiment, cooling tube 334 is coupled to second passage 240 with atleast one connection member 322, such that tube 334 is a distance 337radially inward from passage 228.

FIG. 5 is an enlarged plan view a portion of an alternative embodimentof an integral radiant syngas cooler 300 that may be used with gasifier200 (shown in FIG. 3). FIG. 6 is an enlarged plan view of a portion ofanother alternative embodiment of a radiant syngas cooler 300 that maybe used with gasifier 200 (shown in FIG. 3).

In one embodiment, for example, two cooling tubes 350 and 352 arecoupled together with a connection member 340 (shown in FIG. 4) thatextends therebetween such that a two-tube-bundle 351 is created. In theexemplary embodiment, connection member 340 includes at least fourconnection interfaces 342, 344, 346, and 348. Each connection interface342, 344, 346, and 348 is defined between a portion of a cooling tubeand connection member 340. In the exemplary embodiment, cooling tubes350 and 352 are coupled substantially conlinearly together.

During assembly, connection interfaces 342 and 344 are created againstcooling tube 350, and connection interfaces 346 and 348 are createdagainst cooling tube 352. Specifically, connection interfaces 342 and344 are created as member 340 is welded to cooling tube 350, andconnection interfaces 346 and 348 are created as member 340 is welded tocooling tube 352. In an alternative embodiment, member 340 is coupled tocooling tubes 350 and 352 with any other suitable method.

In an alternative embodiment, as shown in FIG. 5, for example, threecooling tubes 306 are coupled together with two connection members 340and 358 such that a three-tube-bundle 353 is created. Connection members340 and 358 are coupled together in a mating connection. Specifically, anotch 354 is formed on member 340 prior to member 340 being coupled tocooling tubes 350 and 352. More specifically, notch 354 is shaped,sized, and oriented to receive a second connection member 358 therein.

In the exemplary embodiment, second connection member 358 includesconnection interfaces 360, 362, 364, and 366. Second connection member358 is configured to mate with notch 354 such that notch 354 isconfigured to receive second connection member therein.

During assembly of three-tube-bundle 353, in the exemplary embodiment,for example, connection interfaces 342 and 344 are created as member 340is coupled to cooling tube 350, and connection interfaces 346 and 348are created as connection member 340 is coupled to cooling tube 352. Assecond connection member 358 is coupled to a third cooling tube 370,connection interfaces 360 and 362 are created. Moreover, connectioninterfaces 364 and 366 are coupled within notch 354. More specifically,when member 358 is positioned substantially flush within notch 354, ajoint 373 is defined between connection interfaces 364 and 366, andconnection member 340. In the exemplary embodiment, members 340 and 358are welded together. In an alternative embodiment, connection members340 and 358 are not welded together, but rather are coupled togetherwith any suitable method of coupling. In the exemplary embodiment,member 358 is oriented at an angle β with respect to member 340. In theexemplary embodiment, angle β is approximately 90°. Coupling coolingtubes 350, 352, and 370 together with at least two connection members340 and 358 facilitates increasing the surface area of each platen 320such that cooling of syngas within passage 228 is facilitated to beincreased. For example, in the exemplary embodiment, the surface area ofeach platen 320 is increased approximately thirty to forty percent withthe use of a three-tube-bundle as compared to a two-tube-bundle.

In the exemplary embodiment, three-tube-bundle 353 is coupled to otherportions of gasifier 200 with connection members 322. For example,three-tube-bundle 353 may be coupled to, but is not limited to beingcoupled to, other three-tube-bundles, at least one two-tube-bundle, afour-tube-bundle (described below), a single cooling tube, refractorywall 216, and/or passage 228. Specifically, for example, tube-bundle 353includes a pair of connection members 372 and 374 that each extend fromopposite sides of bundle 353 and that are each oriented substantiallycollinearly with connection member 340. In an alternative embodiment,cooling tubes 350 and 352 each include a plurality of connection members322 that extend outward from other locations which facilitate couplingmultiple cooling tubes 306 together.

In an alternative, as shown in FIG. 6, for example, four cooling tubes306 are coupled together with three connection members 340, 358, and 384such that a four-tube-bundle 380 is formed. Connection members 340, 358,and 384 are coupled together in a mating configuration. Specifically, atleast two notches 354 and 382 are formed on member 340 prior to beingcoupled to cooling tubes 350 and 352. More specifically, notches 354 and382 are shaped, sized, and oriented to receive second connection members358 and 384, respectively, therein. In the exemplary embodiment, notches354 and 382 have substantially the same shape.

In the exemplary embodiment, second connection member 358 includesconnection interfaces 360, 362, 364, and 366. Similarly, in theexemplary embodiment, third connection member 384 includes connectioninterfaces 386, 388, 390, and 392. Second connection member 358 isconfigured to mate with notch 354, and third connection member 384 isconfigured to mate with notch 382. Notch 354 is configured to receivesecond connection member 358 therein, and notch 382 is configured toreceive third connection member 384 therein.

During assembly of four-tube-bundle 380, in the exemplary embodiment,for example, connection interfaces 342 and 344 are created as member 340is coupled to cooling tube 350, and connection interfaces 346 and 348are created as member 340 is coupled to cooling tube 352. As secondmember 358 is coupled to third cooling tube 370, connection interfaces360 and 362 are created. Moreover, connection interfaces 364 and 366 arecreated within notch 354. More specifically, when member 358 ispositioned substantially flush within notch 354, joint 373 is definedbetween connection interfaces 364 and 366, and member 340. In theexemplary embodiment, members 340 and 358 are welded together. In analternative embodiment, members 340 and 358 are not welded together, butrather are coupled together with any other suitable method of coupling.

Similarly, during assembly, as third member 384 is coupled to fourthcooling tube 396, connection interfaces 386 and 388 are created.Moreover, connection interfaces 390 and 392 are created within notch382. More specifically, when third member 384 is positionedsubstantially flush within notch 382, a joint 398 is defined betweenconnection interfaces 390 and 392, and member 340. In the exemplaryembodiment, members 340, 358, and 384 are welded together. In analternative embodiment, members 340, 358, and 384 are not weldedtogether, but rather are coupled together with any other suitable methodof coupling. In the exemplary embodiment, member 358 is oriented at anangle β with respect to member 340. In the exemplary embodiment, angle βis approximately 90°. In the exemplary embodiment, member 384 isoriented at an angle θ with respect to member 340. In the exemplaryembodiment, angle θ is approximately 90°.

Coupling cooling tubes 350, 352, 370, and 396 together with at leastthree connection members 340, 358, and 384 facilitates increasing thesurface area of each platen 320 such that cooling of syngas withinpassage 228 is facilitated to be increased. For example, in theexemplary embodiment, the surface area of each platen 320 is increasedapproximately seventy percent with the use of a four-tube-bundle ascompared to a two-tube-bundle.

In the exemplary embodiment, four-tube-bundle 380 is coupled to otherportions of gasifier 200 with connection members 322. For example,four-tube-bundle 380 may be coupled to, but is not limited to beingcoupled to, other four-tube-bundles, at least one two-tube-bundle, athree-tube-bundle, a single cooling tube, refractory wall 216, and/orpassage 228. Specifically, for example, cooling tube-bundle 380 includesa pair of connection members 372 and 374 that each extend from oppositesides of bundle 380 and that are each oriented substantially collinearlywith connection member 340. In an alternative embodiment, cooling tubes350 and 352 each include a plurality of connection members 322 thatextend outward from other locations which facilitate coupling multiplecooling tubes 306 together.

During operation, in the exemplary embodiment, steam 74 is channeledthrough the tube-bundles, as described above, to facilitate coolingsyngas flowing through passage 228 of gasifier 200. In an alternativeembodiment, any suitable cooling fluid is channeled throughtube-bundles. Simultaneously, syngas flowing through passage 228 isdirected around the tube-bundles. As the syngas is circulated around thetube-bundles, heat transfer occurs between steam 74 and the syngas.Specifically, steam 74 absorbs heat from the syngas. The use oftube-bundles increases the surface area of the platens while notincreasing the number of platens within passage 228.

In one embodiment, a method of cooling syngas in a gasifier is provided.The method includes channeling cooling fluid through at least onetube-bundle that includes at least three tubes coupled together within aradiant syngas cooler and extends through a reaction zone of thegasifier, and circulating reactant fluid around the at least onetube-bundle to facilitate transferring heat from the reactant fluid tothe cooling fluid.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralsaid elements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

The above-described methods and systems facilitate circulating syngasthrough cooling tubes coupled within a gasifier. As such, cooling ofsyngas in the integrated gasification system is facilitated to beimproved without increasing the number of components within the IGCC. Asa result, costs associated with the operation and maintenance of theIGCC are facilitated to be reduced, while the efficiency of the IGCC isenhanced.

Exemplary embodiments of gasification systems and methods ofincorporating a radiant syngas cooler into a gasifier to cool the syngaswithin the gasifier are described above in detail. The gasificationsystem components illustrated are not limited to the specificembodiments described herein, but rather, components of each system maybe utilized independently and separately from other components describedherein. For example, the gasification system components described abovemay also be used in combination with different IGCC system components.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A method of cooling syngas in a gasifier, said method comprising:channeling cooling fluid through at least one tube-bundle that includesat least three tubes coupled together within a radiant syngas cooler andextends through a reaction zone of the gasifier; and circulatingreactant fluid around the at least one tube-bundle to facilitatetransferring heat from the reactant fluid to the cooling fluid.
 2. Amethod in accordance with claim 1 wherein channeling reactant fluidaround the at least one tube-bundle comprises channeling syngas aroundthe at least one tube-bundle.
 3. A method in accordance with claim 1wherein channeling cooling fluid through the at least one tube-bundlecomprises channeling steam through the at least one tube-bundle.
 4. Amethod in accordance with claim 1 wherein channeling cooling fluidthrough at least one cooling tube comprises channeling cooling fluidthrough at least one cooling tube to facilitate cooling a wall of thegasifier. 5-17. (canceled)
 18. A method in accordance with claim 3wherein circulating reactant fluid further comprises channeling syngasthrough the reaction zone, wherein heat is transferred from the syngasto the steam.
 19. A method for assembling a radiant cooler for use in agasifier, said method comprising: providing at least one coolingtube-bundle including a first cooling tube, a second cooling tube, and athird cooling tube; coupling a first connection member between the firstand second cooling tubes; and coupling a second connection memberbetween the third cooling tube and the first connection member, whereina portion of the first connection member mates substantially flushagainst a portion of the second connection member.
 20. A method inaccordance with claim 19 wherein providing at least one coolingtube-bundle further comprises providing at least one cooling tube-bundleto facilitate increasing a surface area of the radiant cooler.
 21. Amethod in accordance with claim 19 wherein coupling a first connectionmember further comprises welding the first connection member to thefirst and second cooling tubes, and wherein coupling a second connectionmember further comprises welding the second connection member to thethird cooling tube and to the first connection member.
 22. A method inaccordance with claim 19 further comprising receiving a portion of thesecond connection member within a notch of the first connection member.23. A method in accordance with claim 19 further comprising orientingthe second connection member substantially perpendicularly with respectto the first connection member.
 24. A method for assembling a gasifier,said method comprising: providing a radiant cooler including at leastone cooling tube-bundle and at least two connection members, wherein theat least one cooling tube-bundle includes a first cooling tube, a secondcooling tube, and a third cooling tube; coupling the first connectionmember between the first and second cooling tubes; coupling the secondconnection member between the third cooling tube and the firstconnection member, wherein a portion of the first connection membermates substantially flush against a portion of the second connectionmember; providing a reaction zone; and extending the radiant coolerthrough the reaction zone.
 25. A method in accordance with claim 24further comprising positioning a combustion zone radially inward fromthe reaction zone, wherein the at least one cooling tube-bundle extendsbetween the combustion zone and an outer wall of the gasifier.
 26. Amethod in accordance with claim 24 wherein providing a radiant coolerfurther comprises providing a radiant cooler including at least onecooling tube-bundle to facilitate increasing a surface area of theradiant cooler.
 27. A method in accordance with claim 24 whereincoupling the first connection member further comprises welding the firstconnection member to the first and second cooling tubes, and whereincoupling the second connection member further comprises welding thesecond connection member to the third cooling tube and to the firstconnection member.
 28. A method in accordance with claim 24 furthercomprising receiving a portion of the second connection member within anotch of the first connection member.
 29. A method in accordance withclaim 24 further comprising orienting the second connection membersubstantially perpendicularly with respect to the first connectionmember.